1. Technical Field
The present invention relates to methods for manufacturing outer conductors of higher-order-mode couplers for superconducting acceleration cavities.
2. Description of the Related Art
Superconducting acceleration cavities accelerate charged particles passing therethrough. One way for a superconducting acceleration cavity to deliver predetermined performance is to attach higher-order-mode (HOM) couplers to beam pipes at the ends thereof to remove higher-order modes, which hinder beam acceleration, in other words, to extract higher-order modes induced in the superconducting acceleration cavity outside the superconducting acceleration cavity (Japanese Unexamined Patent Application, Publication No. HEI-10-50499).
A higher-order-mode coupler is composed of an inner conductor, an outer conductor, and a pickup port. The outer conductor is fabricated from a superconducting material such as niobium and is formed in a cylindrical shape that is open at one end surface thereof such that the opening is joined to a beam pipe. The side of the outer conductor has a port that allows a member for extracting higher-order modes to the outside to pass therethrough. An end surface of the outer conductor is thin and has a protruding part. The outer conductor can be deformed by externally holding the protruding part and pushing or pulling it to finely adjust the spacing between the outer conductor and the inner conductor, thereby finely adjusting the wavelength of the higher-order modes to be extracted.